This study examines the potential for point-of-decision prompts (PDPs) to promote healthier food choices among shoppers in a rural, low-income, minority community. We hypothesized that a narrowly defined PDP (focused on fresh produce) would be easier for shoppers to remember than a broadly defined PDP (focused on any healthy items), resulting in a higher proportion of healthy items purchased. PDPs were placed at the entrance to a supermarket in Mission, South Dakota, United States of America, on the Rosebud Sioux Reservation for alternating time periods, July 9-10,2017. Sales records from 653 transactions were retrieved from the supermarket, comprising periods in which PDPs were in place and control periods. We examined the proportion of selected items and proportion of total expenditures that were a) any healthy foods and b) fresh fruits and vegetables. Data were analyzed in 2018. The narrowly defined prompt consistently resulted in a higher proportion of items and expenditures on healthy foods than either the broad prompt or the control condition. Shoppers in the narrow prompt condition purchased and spent significantly more on any healthy foods and fresh produce than shoppers in the control condition. While shoppers in the narrow prompt condition purchased more healthy foods and fresh produce than shoppers in the broad prompt condition, the differences were not statistically significant. Shoppers exposed to the narrow PDP consistently purchased more healthy foods than shoppers in a control group, while shoppers in the broad PDP did not, highlighting the importance of considering cognitive processes when designing health promotion messages.
